Crop science is in a state of flux, caught up in ‘tensions of scale’. These tensions arise from the attempts to address ‘top-down’ issues such as global change impacts with ‘bottom-up’ solutions such as biotechnology. The rapidly changing global environment impacts on the management of farms, fields, crops and plants. However, as the resolution of spatial scale increases, these global impacts are increasingly difficult to quantify. Similarly, rapid biotechnological developments provide new insights and skills at the molecular, genome and cell levels, but with decreasing spatial resolution, environmental interactions increase, making it often difficult to quantify the impact of biotechnology at crop, field, farm or regional levels. Attribution of cause and effect becomes increasingly intractable as the scale difference between the issues and the proposed technological solution increases. Correctly matching problems of societal importance with science-based solutions is a challenge that requires good, quantitative modelling at all scales.